1. Field of the Invention
The present invention relates to an electrical socket, and particularly to a ZIF (Zero Insertion Force) mobile socket for use with a PGA (Pin Grid Array) chip.
2. Description of the Related Art
A ZIF socket is often used to mount a PGA chip onto a printed circuit board (PCB). Referring to FIGS. 5 and 6, one example of such connectors 6 comprises a base 7, a cover 8 mounted onto the base 7, a plurality of electrical contacts (not shown) received in the base 7, a metallic cam 9, a metallic ring 91, and a metallic washer 92. The metallic ring 91 is assembled in the cover 9 of the socket 6 by loosely fitting, interferentially fitting, or by being adhesively bound into a hole in the cover 8. The cover 8 is actuated to slide on the base 7 by the rotation of the metallic cam 9 in the ring 91 and a hole of the base 7, thereby causing pins of the PGA chip mounted on the cover to engage with/disengage from the electrical contacts in the base 7.
The metallic cam 9 comprises a riveting portion 93 to be riveted to the washer 92 to prevent the cam 9 from falling off from the base 7 and the cover 8. The washer 92 is generally planar and has thus a uniform thickness throughout the configuration thereof. The washer 92 is also comparatively slim since the electrical socket 6 as whole is small due to the application thereof. During the course of riveting the riveting portion 93 to the washer 92, the washer 92 is in the danger of whole deformation because of the uniform thickness thereof and the comparatively small dimension thereof. Furthermore, the washer 92 is partly supported by a bottom wall of the base 7, so the deformation of the washer 92 sometimes causes the washer 92 to interferentially engage with the bottom wall of the base 7 because materials from which the washer 92 and the base 7 are made are different and the force needed to rivet the riveting portion 93 to the washer 92 is large. When the washer 92 engages with the base 7, the rotation of the metallic cam 9 will be adversely affected.
Therefore, an improved washer is desired to overcome the disadvantages of the related art. An approach is made as disclosed in the copending application with a Ser. No. 10/108,124 filed on Mar. 27, 2002 and the same assigned with the instant invention.
The major object of the present invention is to provide a ZIF PGA socket having a washer which ensures the rotation of a metallic cam of the ZIF PGA socket.
An electrical socket in accordance with the present invention comprises a base, a cover slidably mounted onto the base, a metallic ring secured in the cover, a cam partially received in the ring, a plurality of electrical contacts received in the base, and a washer. The base comprises a first flange located at one side thereof and defining a hole extending through the first flange. A plurality of passageways are defined in the base and each passageway accommodates one of the electrical contacts. The cover defines a plurality of passages corresponding to the passageways of the base into which pins of a PGA package mounted on the cover fit. The cover also forms a corresponding second flange which cooperates with the first flange, and the second flange defines an aperture therethrough corresponding to the hole of the base. The cam comprises a head, an upper disk, a lower disk and a riveting portion. The coincident rotational axes of the head and the upper disk are offset from the rotational axis of the lower disk. The upper disk is received in the ring while the head is supported a top face of the cover. The lower disk of the cam extends through the hole of the first flange. The washer comprises a support portion to which the riveting portion of the cam is riveted and a peripheral portion has no engagement with a bottom face of the base. The support portion is thicker than the peripheral portion to be supported by the lower disk in the course of riveting the riveting portion of the cam thereto and to provide a strength to endure a riveting force applied thereto.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.